class A
{
    public void f()
    {
         System.out.printf("AAAA\n");
    }
}
class B extends A
{

}
public class TestObject
{
    public static void main(String[] args)
    {
        B bb = new B();
        System.out.printf("%s\n",bb.toString());
    }
}
/*
每个超类都自动继承了java.lang.Object（对象）类
*/